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MORE ON THIS: In a previous Fact of the Week, we learned how plankton helps the oceans ‘biological pump’, a process that supports the global carbon cycle by removing carbon from the air and storing it in the deep sea. This week, we’re going to talk about the largest living creatures in the ocean, whales, and their role in the carbon cycle. Their movements, deaths, and even feces all contribute to the ‘whale pump’ which works with the biological pump to promote carbon storage.

Movement: When whales swim from deep waters to the surface, they move nutrients up with them. Bringing nutrients to the surface increases the food source for phytoplankton, which play the first part in carbon uptake.

MORE ON THIS: It is easy to see the beauty of coral reefs when snorkeling or diving during the day, but have you ever seen the colors of coral at night?

Coral reefs are known to put on a light show known as bio-fluorescence. A family of proteins provides this fluorescence by absorbing one color and emitting another. Each protein provides a different color; the most common is the green fluorescent protein known as GFP. When the wavelengths of color are absorbed then re-emitted, some of the energy is lost. This changes the wavelength, which determines the color.

Species of coral known to give off this fluorescence are found in Hawai‘i and can be seen on night dives with special dive lights. If you’re interested in seeing this phenomenon, you can contact your local dive shop to ask about night diving to see fluorescent coral or, if you’d like to stay dry, you can visit the Maui Ocean Center which has some of this coral on exhibit.

MORE ON THIS: To native Hawaiians, this furry creature may be referred to as ‘llioholoikauaua, but you personally know them as Hawaiian monk seals. These monk seals are endemic, meaning they are only found in Hawai‘i. They are one of the most endangered animals in the world, with their population of about 1,100 still declining.

Monk Seal Resting

These marine mammals are semiaquatic, spending most of their time at sea and some of their time on land. “Hauling out” is a process where the seal goes onto the beaches to sleep, nurse, molt and rest. Here, a mother will nurse her pup for about 6 weeks and then the roughly 200-pound pup will have to fend for itself. An adult will grow from 6 to 7.5 feet in length and will weight between 375 to 600 pounds. They are generalist feeders, feeding on what is readily available, such as squid, eel, octopi, fish, and crustaceans.

MORE ON THIS: In Hawai‘i, Hawksbill turtles mostly nest on Hawai‘i Island, but Maui is home to some of the nesting beaches for ten of these turtles. Beginning around age 20, a female will return to the area where she was born between May and October every 3 to 9 years to lay her eggs. Hawksbills will nest at night and will lay 2-5 sets of eggs, or clutches, in the same season. Each clutch will be laid approximately 16-23 days apart. To lay eggs, the turtle will haul out onto a beach to find a suitable area, dig a deep pit using her flippers, and then fill the pit with her eggs. A single clutch averages 180 eggs. Once she is done laying her eggs, she will use her flippers to fill the hole in with sand before returning to the sea.

MORE ON THIS: Recent research has suggested that bottlenose dolphins have individually unique signature whistles that are equivalent to human names. During the first few months of life, a dolphin will develop its own signature whistle made up of a series of sounds and notes. Dolphins will also adopt the signature whistle of other dolphins in the pod to identify and communicate with different individuals, specifically close associates or those with strong social bonds. When a dolphin emits its own signature whistle, a dolphin that is a close associate will reply with a copied version of the whistle with a few subtle alterations that differentiates the signature whistle from the copied whistle. This allows the second dolphin to relay information back to the first dolphin; the alterations to the whistle may also give information about who the second dolphin is.

Many species of dolphins live in fission-fusion societies, this means that the size and composition of the pod will change as time passes. When pods merge together, vocal signatures are exchanged in order to learn about the identities of individual members of the new pod. These exchanges are generally repeated several times during the interaction to either improve the probability of correct identification, or provide additional information with each exchange.

FACT OF THE WEEK: The underside of a whale’s tail, called the flukes, is not the only characteristic that can be used to photo-identify baleen whales.

MORE ON THIS: You may already know that humpback whales have individually unique tail flukes, like a human fingerprint, and can be identified by photographing these. In addition, each humpback whale also has a unique dorsal fin that allows researchers to track and study individual whales using photo-identification techniques. But did you know that other species of baleen whales are identified using other body parts?

Humpback whale flukes. Photographed under NOAA permit # 16479.

Gray whales don’t actually have a dorsal fin; instead they have a series of “knuckles” along their back. Researchers can use the shape of these knuckles, as well as mottling, scarring, and barnacle patterns on the whale’s back to identify individuals.

Minke whales are identified using nicks or notches in their dorsal fins, or by unusual dorsal fin shape, similar to photo-identification in dolphins. They can also be identified on the basis of lateral body pigmentation.